Some in ceiling speaker systems are mounted to a ceiling material in such a manner that the ceiling material is sandwiched and retained between retaining members. However, when the in ceiling speaker system has a heavy weight or the ceiling material is thin, it is not firmly mounted.
In order to achieve firm mounting and to prevent the in ceiling speaker system from falling off, an auxiliary mounting device is sometimes employed (e.g., see “Control Contractor Ceiling Loudspeakers Owner's Manual,” “JBL Professional, page 7” “Bose Freespace Model 8 And Model 32 Loudspeakers Installer's Guide,” by Bose Corporation, page 4 to 12, May 6, 2002”).
FIG. 11 is a perspective view showing an example of such a auxiliary mounting device. This auxiliary mounting device 110 mainly comprises a ceiling pan 111, and a pair of support rails 121. The ceiling pan 111 is secured to the support rails 121 at a desired position in a longitudinal direction of the support rails 121.
FIG. 12 is a longitudinal sectional view showing a state in which an in ceiling speaker system 200 is mounted to a ceiling by using the auxiliary mounting device 110.
This ceiling structure is a drop ceiling structure employed in U.S. A ceiling material 131 is placed on a steel structure 130 having a T-shaped transverse cross-section, which is called T grid. The auxiliary mounting device 110 is placed on the ceiling material 131. An in ceiling speaker unit 200 is mounted through an opening formed in the ceiling material 131. The in ceiling speaker unit 200 includes a fixed retaining member 201 which is integral with a front panel and a movable retaining member 202 positioned behind the fixed retaining member 201. When a threaded member 203 is rotated to be fastened, the movable retaining member 202 moves downward, and the fixed retaining member 201 and the movable retaining member 202 sandwiches and retains the ceiling material 131 and the ceiling pan 111.
Since the ceiling pan 111 and the ceiling material 131 are sandwiched and retained together, the ceiling material 131 is not damaged if a large force is applied to sandwich and retain them. Therefore, the in ceiling speaker system 200 is firmly mounted to the ceiling. If the ceiling material 131 falls off from the steel structure 130 having the T-shaped cross-section for some reasons, the support rails 121 engage with the steel structure 130, so that the in ceiling speaker system 200 does not fall off.
There are various types of ceiling structures, other than the drop ceiling structure of FIG. 12. By way of example, there are ceiling structures in which construction elements 133 called a M bar shown in FIG. 13(a) or construction elements 136 called a C channel shown 13(b) are provided above the ceiling.
FIG. 13(c) is a longitudinal sectional view showing a state in which the auxiliary mounting device 110 of FIG. 11 is mounted to the ceiling structure in which the ceiling material 134 is threadedly engaged with the M bars 133 provided in parallel. As should be appreciated from FIG. 13(c), the construction elements (M bars) 133 protrude upward from the rear surface of the ceiling material 134, unlike the drop ceiling structure of FIG. 12. So, the ceiling pan 111 of the auxiliary mounting device 110 is distant from the rear surface of the ceiling member 134. When the in ceiling speaker system 200 of FIG. 12 is mounted to the ceiling, and the ceiling material 134 and the ceiling pan 111 are retained with a large force between the fixed retaining member 201 and the movable retaining member 202, the ceiling material 134 is likely to be damaged. As a result, the in ceiling speaker system 200 is not firmly mounted.
FIG. 13(d) is a longitudinal sectional view showing a state in which the auxiliary mounting device 110 is mounted to the ceiling structure in which the ceiling material 134 is threadedly engaged with the M bars 133 provided in parallel and a plurality of C channels 136 are provided on the M bars 133 to extend in a direction perpendicular to the M bars 133. As should be appreciated from FIG. 13(d), the construction elements (M bars 133 and C channels 136) protrude further upward from the rear surface of the ceiling material 134. Since ceiling pan 111 of the auxiliary mounting device 110 is more distant from the rear surface of the ceiling material 134, the in ceiling speaker system is not firmly mounted.